| **Navigation:**  [[templates.htm|Templates]] > Guide to all Templates > [[additional libraries and templates.htm|Additional Libraries and Templates]] > Finance Library >====== PREPERS (periods of annuity with prepayment) ====== | [[prefv  future value with prepayment .htm|{{btn_prev_n.gif|Previous page}}]][[additional libraries and templates.htm|{{btn_home_n.gif|Return to chapter overview}}]][[prerate  rate of annuity with prepayment .htm|{{btn_next_n.gif|Next page}}]] |
|  ||

**PREPERS**(//presentvalue,rate,payment,futurevalue//)

| **PREPERS** | Computes the number of periods required to reach a targeted future value. |
| //presentvalue// | A numeric constant or variable containing the present value of the investment. |
| //rate// | A numeric constant or variable containing the //periodic //rate of return. |
| //payment// | A numeric constant or variable containing the periodic payment. |
| //futurevalue// | A numeric constant or variable containing the amount of the desired or targeted future value of the investment. |

**PREPERS **determines the number of periods required to reach a desired amount (//futurevalue//) based upon a starting amount (//presentvalue//), a periodic interest rate (//rate//), and a payment amount (//payment//). If payments occur at the end of each period, use the PERS function, which calculates interest accordingly.

Periodic rate may be calculated as follows:

PeriodicRate = AnnualInterestRate / (PeriodsPerYear * 100)

{{c6h0012.jpg|C6H0012.jpg}}

If the present value is less than the future value (annuities), payments are positive, and conversely, if the present value is greater than the future value (loans), payments are negative.

**Return Data Type:**     DECIMAL

**Internal Formulas:**

{{prepers.jpg|PREPERS.jpg}}

The PREPERS function performs binary search iterations to home in on the periods value. If more than 50 such iterations are required, a value of zero is returned.

**Example:**

**  PeriodicRate = AnnualRate / (PeriodsPerYear * 100)**

**  IF TimeOfPayment = 'Beginning of Periods'**

**   TotalPeriods = PREPERS(PresentValue,PeriodicRate,Payment,FutureValue)**

**  ELSE**

**   TotalPeriods = PERS(PresentValue,PeriodicRate,Payment,FutureValue)**

**  END**